16-1772888-G-A

Position:

• chr16-1772888-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The ENST00000397375.7(MRPS34):​c.232C>T​(p.Arg78Cys) variant causes a missense change. The variant allele was found at a frequency of 0.000000771 in 1,297,742 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 35)
  • Exomes 𝑓: 7.7e-7 (0 hom.)
• Consequence: MRPS34 ENST00000397375.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.83

Genes affected

MRPS34 (HGNC:16618): (mitochondrial ribosomal protein S34) Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 28S subunit protein. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

EME2 (HGNC:27289): (essential meiotic structure-specific endonuclease subunit 2) EME2 forms a heterodimer with MUS81 (MIM 606591) that functions as an XPF (MIM 278760)-type flap/fork endonuclease in DNA repair (Ciccia et al., 2007 [PubMed 17289582]).[supplied by OMIM, Mar 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.877

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MRPS34	NM_023936.2	c.232C>T	p.Arg78Cys	missense_variant	1/3	ENST00000397375.7	NP_076425.1
EME2	NM_001257370.2	c.-340G>A		5_prime_UTR_variant	1/8	ENST00000568449.7	NP_001244299.1
MRPS34	NM_001300900.2	c.232C>T	p.Arg78Cys	missense_variant	1/3		NP_001287829.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MRPS34	ENST00000397375.7	c.232C>T	p.Arg78Cys	missense_variant	1/3	1	NM_023936.2	ENSP00000380531	P1
MRPS34	ENST00000177742.7	c.232C>T	p.Arg78Cys	missense_variant	1/3	1		ENSP00000177742
EME2	ENST00000568449.7	c.-340G>A		5_prime_UTR_variant	1/8	1	NM_001257370.2	ENSP00000457353	P1

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome AF: 7.71e-7 AC: 1 AN: 1297742 Hom.: 0 Cov.: 63 AF XY: 0.00 AC XY: 0 AN XY: 633858

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.61e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 35

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 17, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. This variant has not been reported in the literature in individuals affected with MRPS34-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 78 of the MRPS34 protein (p.Arg78Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.32
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Benign	0.37	T;D
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.88	D;D
MetaSVM	Benign	-0.75	T
MutationAssessor	Uncertain	2.3	.;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.94	D
PROVEAN	Pathogenic	-5.7	D;D
REVEL	Uncertain	0.50
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.85
MutPred		0.75		Loss of MoRF binding (P = 6e-04);Loss of MoRF binding (P = 6e-04);
MVP		0.22
MPC		3.3
ClinPred		1.0	D
GERP RS		3.7
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.7
Varity_R		0.77
gMVP		0.83

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1410732345; hg19: chr16-1822889;